Method of making 1-phenyl-2-3-dimethyl-4-sulfamino-5-pyrazolone and its salts.



" UNITED sTAtrns PATENT orrmon...

EMIL SCHEITLIN, OF ALTSTETTEN, NEAR ZURICH, SWITZERLAND.

METHOD 'OF MAKING l-PHENYL-Q.3-DIM'ETHYL-QSULFAMINO-5-PYiRAZOLONE AND ITS SALTS.

' 2.3-Dimethyl-4-Qulfamino-5-Pyrazolone and Its Salts; and I do herelty declare the following to lie a full, clear, and exact descriptionof the invention, such as will enalle others skilled in theart to which it apperta'ins to make and use the same.

My invention relates to a new product and its method of manufacture, the same ltelng r a new chen'tical compound denominated as l-pheny1-3Bali-methyl -4-sulfamino 5 -pyrazolone, used as a pharmaceutical preparation and in photography. 1 i

l have found that 1-phenyl-2.3-di-mcthyl- 4-nitroso-5-pyrazoione when treated with asuital-le lri-suliite, as sodium lri-sulfite, is readily converted into its suit-amino eomhination in accordance with thefollowing reaction:

oxid, as follows:

It has not heretofore been known to decompose a nitroso group hy the actionof SOCllllIIl hi-sulfite, for the purpose of forming a sulf-amino comtinatiou, and this method of reduction is very advantageous by reason of the facility with whichit may he carried out. The resulting product when properly separated contains no impurity.

From solutions of the product containing hydrochloric acid and sodium ehlorid, thesulf-amino coml:ination crystallizes in fine needle-like crystals, and the whole solution quickly lrecomes thick with these crystals. The crystals are white, and when heated to about 140 C. lregin to'decompose, and at ahout 180 to 190 they turn blue-brown to black, and at a higher temperature they l eginto turn to carbon. 7

The sulf-amino comtination is quite stalle against the action of dilute mineral acids in the cold, but when heated with dilute mineral Specification of Letters Patent. Application filed. July 11, 1907. serial No. 333,291. ('S pecimens.)

Patented Aug. '3, 1909.

' lacids to about 40to (1;, they are gradually hydrolized with the formation of sulfuric-amino-pyrazolone.

' Concentrated sulfuric acid dissolves the crystals with the formation of a yellow solution unaltered by slight heating. On'the addition of water the solution assumes the color of a very dilute permanganate solution, a sign that sulfuric-amino-pyrazolone has been formed.

The sulf-aminocomlinationgives with a solution of iron-chlorid an intense orangered color, that sharply distinguishes this compound from the coloring obtained hy iron ehlorid and amino-pyrazolone. With alkalies it forms alkaline salts readily solul le in water, but insolul le inconcentrated alkaline solutions. It is insolul le in sodiumchlorid solutions; in pure water and alcohol the crystals are soluble with difficulty and very slowly, and likewise insolultle in the used as a starting material for: l-phenyl-2.3-

This action takes place quickly on a water hath.

di-methyl-4 amino-5-pyrazolone and other derivatives, and in many cases it need not be separated from its solution. As

'an example, to the 1-phenyl2.3-di-methyl- 4-nitroso-5-pyrazolone, derived from 188 parts of 1-phenyl-2.3 di-methyl-5-p razolone and which need not be separate from its solution, is added 1000volumes of concentrated sodium bi-sulfite solution, and the mixture is boiled until isulfur+di-oxid is no longer given off and the solution is only slightly yellow. The solution is then evaporated in an open vessel or. in vacuum until it is reduced to one-third or one-fourth its volume, according to whether a concentrated or a dilute solution has been used for the formation of l-phenyl-2.3-di-methyl-4-nitrosofopyrazolone. The end of evaporation 1s 1ndicated by the formation of a scum of sodium sulfate on the solution. The solution is then 'cooled and separated from the sodium sulfate crystals formed, and mixed with 33() volumes of concentrated hydrochloric acid tion of sulfur di-oxid,

7 After standing for about twenty-four hours the crystals of 1-phenyl-2.3-d1-methyl- 4-sulfite-annno-5-Eyrazolone' are 7 se ar'ated from the mother 'quor, preferably, ut not necessarily, byttpressing, and the crystalswashed wltha ewaterand alcohol, After allowing the solution. to stand for a longer time the residue of the sulf-amlno-pyrazo- I lone is crystallized out. The acid is monocarbonates.

(Phenyl) -Iclaim- 1. The process of making 1- henyl- 73.3 di-methyl-4'-su1f-amino-5-pyrazo one, which com rises reacting upon l-phenyl-ZB-dimet yl-4-nitroso-5-pyrazolone witha bi-sulfite of a metal, to convert the nitroso group thereof into the sulf-amino-grou 2. The process ofmakingl-plienyl-QB-dimethyl-4-sulf-amino --5- pyrazolone, which consists in reacting upon 1'-phenyl-2.3-di-- meth l-4-nitroso-5-pyrazolone with sodiumbi-su fite at a temperature above normal.

3.' As a new product, 1- phenyl-2.3-dimethyl -4- sulf-annno -5- pyrazolone, a white crystalline compound, giving with ironl chlorid an intense orange-red color and capable of acting as a photographic developer.

4. The processof making 1--phenyl-2.3-dimethyl -4-'sulf-amino 5-pyrazolone, which consists in reacting upon 1-phenyl 2 .3-dimethyll-nitroso-5-pyrazolone with a bi-sul-- fite of an alkaline metal at a temperature' above normal.

In testimony that I claimthe foregoing as my invention, I have signed my name presence of two subscribing witnes'ses' EMIL SCHEITLIN.

Witnesses: 5 v v A. LIEBERKNECHT, WERNER DIETBIOH. 

